The effects of Hematodinium sp infection on aspects of the respiratory physiology of the Norway lobster, Nephrops norvegicus (L)

Populations of the Norway lobster Nephrops norvegicus from the west coast of Scotland are infected with a dinoflagellate parasite belonging to the genus Hematodinium. The rates of oxygen consumption of infected N. norvegicus were significantly greater than those of uninfected lobsters. This may be attributed partly to the oxygen demands of the very large numbers of parasite cells present in the haemolymph and in the body tissues since the rates of oxygen consumption of the haemolymph of heavily-infected lobsters were approximately 5 times greater than those of uninfected or less heavily infected lobsters. The presence of such large numbers of cells in the haemolymph, which may block haemal sinuses in the gills, appears to compromise oxygen delivery to the tissue of the host since the PO2 of the haemolymph of heavily-infected lobsters (PaO2=2.99+/-0.91 kPa) was significantly lower than that of uninfected lobsters (PaO2=9.4+/-1.39 kPa). The oxygen carrying capacity of the haemolymph of heavily-infected lobsters was reduced by approximately 50% compared with that of uninfected animals. In addition, the haemolymph pH was lower and the L-lactate concentration was significantly higher in infected lobsters indicating that these animals resort, in part, to anaerobic metabolism.